This time the issue is marijuana. Specifically legal marijuana, which is now coming to Washington and Colorado and could make pot very cheap if the federal government doesn't get too nosy. Opposition to marijuana legalization is grounded on a social level by public health concerns, a law-and-order mentality, and leftover culture-war politics from the 1960s. But from a financial perspective, the muscle was being wielded by vendors of "medical marijuana":

Though one might assume that legalization would be opposed primarily by law enforcement and social conservatives, nearly all of the money donated to fight the ballot measure in Washington came not from such groups but rather from the existing medical marijuana industry, according to state campaign contribution filings.

The main group formed to oppose the legalization ballot measure, "No on I-502," was directed by Steve Sarich, a patients' rights advocate who runs a local dispensary or "access point," as he calls it. He says neither he nor his campaign's contributors opposed the measure for financial reasons. "There may be a few that are making some money," he told HuffPost Monday, "but most of them are just paying the rent."

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This is one of the odder cases of unintended consequences in recent American political history. While marijuana does have some therapeutic value, I think it's pretty obvious that the intention of the medical marijuana movement has always been to push policy down a slippery slope toward legal tolerance of recreational marijuana use. But rather than creating a self-enforcing interest group spiral, it's actually created a brand-new interest group to join the alcohol lobby in opposing legal pot.